T 1040/03 03-11-2005

1. The patent relates to cylindrical members of sheet metal having a reduced diameter end portion, such as are used for the housings of motor vehicle silencers and catalytic converters. Previously such cylindrical members when provided with a concentric end portion have been manufactured by pressing the end portion to a nearly conical form which is then finished in a spinning operation. However, manufacture of cylindrical members having end portions eccentric to the main axis previously has involved pressing the end portion and joining it to the main portion. According to the present patent an eccentric end portion may be formed on a cylindrical member by a spinning operation.

Sufficiency of disclosure

2. The contested decision revoked the patent because the Opposition Division considered the disclosure to be insufficient for those two of the three variants covered by method claim 1 in which the cylindrical member is rotated. The problem was considered to result from an eccentricity of the formed portion relative to the main axis arising from the forming operation itself, resulting in a movement termed "wagging". In the final sentence on page 4 of the decision the Opposition Division states: "In order to avoid such a wagging movement it would be necessary also to offset the rotational axis of the cylindrical member from its central axis until the rotational axis coincides with the longitudinal central axis of the formed eccentric portion". However, the wording of claim 1 specifies "driving … said cylindrical member … about the longitudinal central axis (Xr) offset from the central axis (Xt) of said cylindrical member". In other words, claim 1 specifies that the cylindrical member always rotates about the eccentric axis so no adjustment to avoid "wagging" would be necessary. Indeed, during the oral proceedings held before the Board the respondent accepted that since claim 1 specifies that the rotation of the cylindrical member is around the eccentric axis the "wagging" problem which formed the basis of the revocation action would not arise. Nevertheless, the respondent still sees difficulties arising from a need to adjust the radial position of the cylindrical member whilst it is rotating.

2.1 The patent specification discloses the concept of performing a plurality of passes in order to achieve a degree of deformation of the cylindrical member which exceeds that to which the material may be subjected in a single pass and the eccentricity of the rotational axis changes with each pass. It discloses with particular reference to figure 6 creating in this way a smoothly tapered surface. As a result of the smooth taper the eccentricity of the end portion changes continuously along its length. In the opinion of the respondent this would necessitate displacing the rotational axis of the rotating cylindrical member not only between passes but also during the initial longitudinal movement of each pass. Whether displacement of the rotational axis of the rotating cylindrical member during a pass would in fact be necessary would depend on such factors as the degree of taper of the end portion, the change in radial dimension per pass and the form of the spinning tool. If indeed for a particular combination of parameters a radial displacement during rotation were necessary, the question prompted by the respondent is whether the skilled person would be capable of putting the method into effect without the need to exercise inventive skill. In particular the respondent considered that there would be a need to disclose splines, a clamp, an actuator, electrical contact means, a displacement transducer and means for compensating for eccentricity of the centre of gravity of the cylindrical member. However, all of these features are conventional and the Board believes that neither these nor any other features necessary to provide for radial movement of the cylindrical member during its rotation extend beyond the knowledge of the skilled person.

2.2 The standard of disclosure set out in the ground for opposition according to Article 100(b) EPC is "in a manner sufficiently clear and complete for it to be carried out by a person skilled in the art". The Board considers that the skilled person would be capable of putting the method into effect without the burden of exercising inventive skill and that the standard set by the EPC has been reached without the need for a detailed disclosure of the contested variants. In the present case the scope of patent protection therefore has not been extended to subject-matter which, after reading the patent specification, would still not be at the disposal of the skilled person. The technical contribution to the art in the present case relates to the concept of a spinning operation involving eccentric rotational engagement of a cylindrical member. This concept is applicable whether the cylindrical member is rotating or stationary and the extent of the patent monopoly therefore is justified.

2.3 On the basis of the foregoing the Board concludes that the requirements of the EPC in respect of sufficiency of disclosure of the method are satisfied. Claim 9 relates to an apparatus in which only the rollers are rotated and has not led to any objection in accordance with Article 100(b) EPC by either the respondent or the Opposition Division.

Novelty and inventive step

3. D1 relates to an apparatus for forming the end portion of a cylindrical member into "various shapes" by spinning. The cylindrical member is supported in a clamp and the rollers are supported for rotational engagement with the end portion of the cylindrical member. In figure 4 a cylindrical member illustrated mounted in the apparatus has a tapered end portion. The inventive concept addressed by D1 relates to the radial adjustment of the rollers using a planetary gear arrangement. The respondent considers that D1 discloses all features of the subject-matter of the apparatus claim 9. The appellant is in agreement with the respondent as regards most aspects of the disclosure of D1 and the Board will restrict itself to consideration of the only matter which is the subject of dispute, relating to eccentricity of the end portion relative to the central axis of the cylindrical member.

3.1 In figure 4 of D1 the cylindrical member is shown supported in the clamp with the tapered end portion close to the rollers. As illustrated the end portion of the cylindrical member is somewhat eccentric with respect to the main portion but this is the only indication of any such eccentricity. In particular, D1 is silent as regards the construction of the clamp and the arrangement for the radial adjustment of the rollers, to which the document primarily relates, has no provision for eccentricity. The boards of appeal have developed case law as regards the requirements to be met when assessing whether a feature shown solely in a drawing forms part of the state of the art. According to T 204/83 (OJ EPO 1985, 310) such features are to be considered as disclosed when a person skilled in the art is able, in the absence of any other description, to derive a technical teaching from them. Moreover, as stressed by the appellant with reference to T 970/00 (supra) it is not correct to interpret the disclosure of the prior art so as to distort or misrepresent it in the light of the present patent. The drawing of D1, figure 4 is of good quality but it is not of engineering detail drawing standard and without knowledge of the present patent specification the skilled person would not derive a technical teaching of providing an eccentric end portion, particularly as this is not a common feature in the art of spinning.

3.2 The respondent argues that it would be normal to provide in D1 a clamp having adjustment to provide for various diameters of cylindrical member; since the adjustable clamp would be suitable for locating the cylindrical member eccentrically the subject-matter of claim 9 would not be new. However, whilst it may be common to provide a clamp being adjustable for various diameters of cylindrical member it is not necessarily so since a machine may be adapted to accept a single cylindrical member. Such is the case in the patent specification where the vertical clamps shown in the embodiments of figures 2 and 16 have no height adjustment for the lower jaw so that the longitudinal centre-line of a cylindrical member of a particular diameter will always be within the same horizontal plane as the rotational axis of the rollers. Similarly, the apparatus according to D4 is adapted to mount a particular article.

3.3 It follows from the foregoing that the subject-matter of each of claims 1 and 9 is new.

4. It is acknowledged in the patent specification that it was known to press-form a near-conical concentric end portion of a cylindrical member and then to use a spinning operation to form it into a tapered end portion concentric with the main portion of the cylindrical member. However, it has previously been the practice that when an eccentric arrangement was required this was achieved by assembling two separately fabricated portions, resulting in a higher-cost article having lower strength. The subject-matter of method claim 1 accordingly provides a solution to the problem of forming an eccentric end portion on a cylindrical member having improved mechanical properties and in an economical way. As discussed above, D1 contains no information relevant to the formation of an end portion eccentric to the axis of the main body of the cylindrical member.

4.1 D4 relates to an apparatus for spinning a tubular nose on a cup-shaped sheet metal article at an angle to the main axis of the article. In the preferred embodiment the article is formed initially with a frusto-conical projection eccentrically and angularly positioned relative to the central axis of the main body and the projection is developed into the elongated tubular nose by spinning. The apparatus comprises a platform mounted for rotation about an axis and which locates the article with the frusto-conical projection concentric with the rotational axis. A mandrel having substantially the same shape as the final shape of the tubular nose is positioned within the projection and a hand tool is used to form the material around the surface of the mandrel.

4.2 The teaching of D4 does not go beyond the prior art acknowledged in the patent specification relating to performing a spinning operation on a press-formed near-conical concentric end portion of a cylindrical member. In both D4 and that acknowledged prior art the spinning operation merely develops the shape of a portion rotating about its own central axis; no eccentricity of parallel axes results from the spinning operation. Indeed, in the embodiment and all of the claims according to D4 the axis of rotation and the longitudinal central axis of the main body are mutually angled. By comparison, according to present claim 1 the spinning operation forms a reduced-diameter end portion as a result of the roller engaging the cylindrical member eccentrically during rotation about an axis parallel to the existing longitudinal central axis of the cylindrical member. It follows that a combination of D1 and D4 would not result in the subject-matter of present claim 1.

4.3 As already set out under 4.2 a combination of D1 and D4 does not contain any teaching relevant to a spinning operation involving rotation about an eccentrically positioned axis parallel to the longitudinal central main axis of a cylindrical member. The skilled person would not be encouraged by this combination of prior art teachings to modify the apparatus of D1 to provide for such offset rotation. Indeed, D4 teaches the use of a mounting jig specially adapted for that article and to locate it in a concentric position. A combination of D1 and D4 therefore would not lead the skilled person to arrive at the subject-matter of present claim 9 in an obvious way.

5. On the basis of the foregoing the Board concludes that the subject-matter of present claims 1 and 9 involves an inventive step. Since claims 2 to 8 and 10 to 14 contain all features of claims 1 and 9 respectively this conclusion applies equally to those claims.